The advent of the screw gun and numerous types of driver bits for drills have made screws a mainstay of the carpentry trade. With literally hundreds of different screws and types of fastening hardware available, there is a specific screw for almost every job. But, for most carpentry jobs you will only need to consider a few general-purpose types. Although nails are still preferred for framing jobs, screws have replaced nails for hanging drywall, installing blocking between studs, and attaching sheathing and flooring. Screws are also used to attach a workpiece to plaster, brick, or concrete, which requires an anchoring device (opposite page, top).
Screws are categorized according to length, slot style, head shape, and gauge. The thickness of the screw body is indicated by the gauge number. The larger the number, the larger the screw. Large screws provide extra holding power; small screws are less likely to split a workpiece. There are various styles of screw slot, including Phillips, slotted, and square. Square-drive screwdrivers are increasing in popularity because they grip the screw head tightly, but Phillips head screws are still the most popular.